def fnn_deconvolution(F, C0=None, theta0=None, dt=0.02,
learn_theta=(0, 0, 0, 0), params_tol=1E-3,
spikes_tol=1E-3, params_maxiter=10, spikes_maxiter=100,
verbosity=1, plot=False):
"""
Infer spike trains from fluorescence using Fast Non-Negative Deconvolution
---------------------------------------------------------------------------
This function uses an interior point method to solve the following
optimization problem:
n_best = argmax_{n >= 0} P(n | F)
where n_best is a maximum a posteriori estimate for the most likely spike
train, given the fluorescence signal F, and the model:
C_{t} = gamma * C_{t-1} + n_t, n_t ~ Poisson(lambda * dt)
F_{t} = C_t + beta + epsilon, epsilon ~ N(0, sigma)
It is also possible to estimate the model parameters sigma, beta and lambda
from the data using pseudo-EM updates.
Arguments:
---------------------------------------------------------------------------
F: ndarray, [nt]
measured fluorescence values
C0: ndarray, [nt]
initial estimate of the calcium concentration for each time bin.
theta0: len(4) sequence
initial estimates of the model parameters (sigma, beta, lambda, gamma).
dt: float scalar
duration of each time bin (s)
learn_theta: len(4) bool sequence
specifies which of the model parameters to attempt learn via pseudo-EM
iterations. currently gamma cannot be learned, and will raise an error.
spikes_tol: float scalar
termination condition for interior point spike train estimation:
params_tol > abs((LL_prev - LL) / LL)
params_tol: float scalar
as above, but for the model parameter pseudo-EM estimation
spikes_maxiter: int scalar
maximum number of interior point iterations to estimate MAP spike train
params_maxiter: int scalar
maximum number of pseudo-EM iterations to estimate model parameters
verbosity: int scalar
0: no convergence messages (default)
1: convergence messages for model parameters
2: convergence messages for model parameters & MAP spike train
plot: bool scalar
live plot of n and (C + beta), updated during parameter estimation
Returns:
---------------------------------------------------------------------------
n_best: ndarray, [nt]
MAP estimate of the most likely spike train
C_best: ndarray, [nt]
estimated intracellular calcium concentration (A.U.)
LL_best: float scalar
posterior log-likelihood of F given n_best and theta_best
theta_best: len(4) tuple
model parameters, updated according to learn_theta
Reference:
---------------------------------------------------------------------------
Vogelstein, J. T., Packer, A. M., Machado, T. a, Sippy, T., Babadi, B.,
Yuste, R., & Paninski, L. (2010). Fast nonnegative deconvolution for spike
train inference from population calcium imaging. Journal of
Neurophysiology, 104(6), 3691-704. doi:10.1152/jn.01073.2009
"""
tstart = time.time()
nt = F.shape[0]
if theta0 is None:
theta_best = _init_theta(F, dt, hz=0.3, tau=0.5)
else:
theta_best = theta0
# scale F to be between 0 and 1
offset = F.min()
scale = F.max() - offset
F = (F - offset) / scale
sigma, beta, lamb, gamma = theta_best
# apply scale and offset to beta and sigma
beta = (beta - offset) / scale
sigma = sigma / scale
theta_best = np.vstack((sigma, beta, lamb, gamma))
if C0 is None:
C = _init_C(F, dt)
else:
C = C0
if plot:
fig, ax = plt.subplots(2, 1, sharex=True, figsize=(10, 10))
xmax = min(2000, nt)
fr_t = np.arange(xmax) * dt
ax[0].set_ylim(F.min(), F.max())
ax[0].set_xlim(0, fr_t[-1])
ax[0].hold(True)
ax[1].set_ylim(0, 1)
fig.canvas.draw()
C_bg = fig.canvas.copy_from_bbox(ax[0].bbox)
nt_bg = fig.canvas.copy_from_bbox(ax[1].bbox)
F_line, = ax[0].plot(fr_t, F[:xmax], '-b')
C_line, = ax[0].plot(fr_t, C[:xmax] + beta[0], '-r',
scalex=False, scaley=False)
nt_line, = ax[1].plot(fr_t[1:xmax], np.ones(xmax - 1) * lamb * dt,
'-r', scalex=False, scaley=False)
fig.canvas.draw()
time.sleep(0.1)
# if we're not learning the parameters, this step is all we need to do
n_best, C_best, LL_best = estimate_MAP_spikes(
F, C, theta_best, dt, spikes_tol, spikes_maxiter,
verbosity
)
if plot:
F_line.set_data(fr_t, F[:xmax])
C_line.set_data(fr_t, C_best[:xmax] + theta_best[1])
nt_line.set_data(fr_t[1:], n_best[:xmax - 1])
fig.canvas.restore_region(C_bg)
fig.canvas.restore_region(nt_bg)
ax[0].draw_artist(C_line)
ax[0].draw_artist(F_line)
ax[1].draw_artist(nt_line)
fig.canvas.blit(ax[0].bbox)
fig.canvas.blit(ax[1].bbox)
# pseudo-EM iterations to optimize the model parameters
if np.any(learn_theta):
if verbosity >= 1:
sigma, beta, lamb, gamma = theta_best
print('Params: iter=%3i; sigma=%6.4f, beta=%6.4f, '
'lambda=%6.4f, gamma=%6.4f; LL=%12.2f; delta_LL= N/A'
% (0, sigma, beta, lamb, gamma, LL_best))
n = n_best
C = C_best
LL = LL_best
theta = theta_best
nloop_params = 1
done = False
while not done:
# update the parameter estimates
theta1 = _update_theta(n, C, F, theta, dt, learn_theta)
# get the new n, C, and LL
n1, C1, LL1 = estimate_MAP_spikes(
F, C, theta1, dt, spikes_tol,
spikes_maxiter, verbosity
)
# test for convergence
delta_LL = -((LL1 - LL) / LL)
if verbosity >= 1:
sigma, beta, lamb, gamma = theta1
print('Params: iter=%3i; sigma=%6.4f, beta=%6.4f, '
'lambda=%6.4f, gamma=%6.4f; LL=%12.2f; delta_LL= %8.4g'
% (nloop_params, sigma, beta, lamb, gamma, LL1,
delta_LL))
if plot:
C_line.set_data(fr_t, C1[:xmax] + theta1[1])
nt_line.set_data(fr_t[1:xmax], n1[:xmax - 1])
fig.canvas.restore_region(C_bg)
fig.canvas.restore_region(nt_bg)
ax[0].draw_artist(F_line)
ax[0].draw_artist(C_line)
ax[1].draw_artist(nt_line)
fig.canvas.blit(ax[0].bbox)
fig.canvas.blit(ax[1].bbox)
time.sleep(0.1)
# if the LL improved, keep these parameters
if LL1 > LL_best:
n_best, C_best, LL_best, theta_best = (
n1, C1, LL1, theta1)
if (np.abs(delta_LL) < params_tol):
if verbosity >= 1:
print("Parameters converged after %i iterations"
% (nloop_params))
print "Last delta log-likelihood:\t%8.4g" % delta_LL
print "Best posterior log-likelihood:\t%11.4f" % (
LL_best)
done = True
elif delta_LL < 0:
if verbosity >= 1:
print 'Terminating because solution is diverging'
done = True
elif nloop_params > params_maxiter:
if verbosity >= 1:
print 'Solution failed to converge before maxiter'
done = True
n, C, LL, theta = n1, C1, LL1, theta1
nloop_params += 1
if verbosity >= 1:
time_taken = time.time() - tstart
print "Completed: %s" % s2h(time_taken)
sigma, beta, lamb, gamma = theta_best
# correct for the offset and scaling we originally applied to F
C_best *= scale
beta *= scale
beta += offset
sigma *= scale
# since we can't use FNND to estimate the spike probabilities in the 0th
# timebin, for convenience we just concatenate (lamb * dt) to the start of
# n so that it has the same shape as F and C
n_best = np.concatenate((lamb * dt, n_best), axis=0)
theta_best = np.hstack((sigma, beta, lamb, gamma))
return n_best, C_best, LL_best, theta_best
def fnn_deconvolution(F,
C0=None,
theta0=None,
dt=0.02,
learn_theta=(0, 0, 0, 0),
params_tol=1E-3,
spikes_tol=1E-3,
params_maxiter=10,
spikes_maxiter=100,
verbosity=1,
plot=False):
"""
Infer spike trains from fluorescence using Fast Non-Negative Deconvolution
---------------------------------------------------------------------------
This function uses an interior point method to solve the following
optimization problem:
n_best = argmax_{n >= 0} P(n | F)
where n_best is a maximum a posteriori estimate for the most likely spike
train, given the fluorescence signal F, and the model:
C_{t} = gamma * C_{t-1} + n_t, n_t ~ Poisson(lambda * dt)
F_{t} = C_t + beta + epsilon, epsilon ~ N(0, sigma)
It is also possible to estimate the model parameters sigma, beta and lambda
from the data using pseudo-EM updates.
Arguments:
---------------------------------------------------------------------------
F: ndarray, [nt]
measured fluorescence values
C0: ndarray, [nt]
initial estimate of the calcium concentration for each time bin.
theta0: len(4) sequence
initial estimates of the model parameters (sigma, beta, lambda, gamma).
dt: float scalar
duration of each time bin (s)
learn_theta: len(4) bool sequence
specifies which of the model parameters to attempt learn via pseudo-EM
iterations. currently gamma cannot be learned, and will raise an error.
spikes_tol: float scalar
termination condition for interior point spike train estimation:
params_tol > abs((LL_prev - LL) / LL)
params_tol: float scalar
as above, but for the model parameter pseudo-EM estimation
spikes_maxiter: int scalar
maximum number of interior point iterations to estimate MAP spike train
params_maxiter: int scalar
maximum number of pseudo-EM iterations to estimate model parameters
verbosity: int scalar
0: no convergence messages (default)
1: convergence messages for model parameters
2: convergence messages for model parameters & MAP spike train
plot: bool scalar
live plot of n and (C + beta), updated during parameter estimation
Returns:
---------------------------------------------------------------------------
n_best: ndarray, [nt]
MAP estimate of the most likely spike train
C_best: ndarray, [nt]
estimated intracellular calcium concentration (A.U.)
LL_best: float scalar
posterior log-likelihood of F given n_best and theta_best
theta_best: len(4) tuple
model parameters, updated according to learn_theta
Reference:
---------------------------------------------------------------------------
Vogelstein, J. T., Packer, A. M., Machado, T. a, Sippy, T., Babadi, B.,
Yuste, R., & Paninski, L. (2010). Fast nonnegative deconvolution for spike
train inference from population calcium imaging. Journal of
Neurophysiology, 104(6), 3691-704. doi:10.1152/jn.01073.2009
"""
tstart = time.time()
nt = F.shape[0]
if theta0 is None:
theta_best = _init_theta(F, dt, hz=0.3, tau=0.5)
else:
theta_best = theta0
# scale F to be between 0 and 1
offset = F.min()
scale = F.max() - offset
F = (F - offset) / scale
sigma, beta, lamb, gamma = theta_best
# apply scale and offset to beta and sigma
beta = (beta - offset) / scale
sigma = sigma / scale
theta_best = np.vstack((sigma, beta, lamb, gamma))
if C0 is None:
C = _init_C(F, dt)
else:
C = C0
if plot:
fig, ax = plt.subplots(2, 1, sharex=True, figsize=(10, 10))
xmax = min(2000, nt)
fr_t = np.arange(xmax) * dt
ax[0].set_ylim(F.min(), F.max())
ax[0].set_xlim(0, fr_t[-1])
ax[0].hold(True)
ax[1].set_ylim(0, 1)
fig.canvas.draw()
C_bg = fig.canvas.copy_from_bbox(ax[0].bbox)
nt_bg = fig.canvas.copy_from_bbox(ax[1].bbox)
F_line, = ax[0].plot(fr_t, F[:xmax], '-b')
C_line, = ax[0].plot(fr_t,
C[:xmax] + beta[0],
'-r',
scalex=False,
scaley=False)
nt_line, = ax[1].plot(fr_t[1:xmax],
np.ones(xmax - 1) * lamb * dt,
'-r',
scalex=False,
scaley=False)
fig.canvas.draw()
time.sleep(0.1)
# if we're not learning the parameters, this step is all we need to do
n_best, C_best, LL_best = estimate_MAP_spikes(F, C, theta_best, dt,
spikes_tol, spikes_maxiter,
verbosity)
if plot:
F_line.set_data(fr_t, F[:xmax])
C_line.set_data(fr_t, C_best[:xmax] + theta_best[1])
nt_line.set_data(fr_t[1:], n_best[:xmax - 1])
fig.canvas.restore_region(C_bg)
fig.canvas.restore_region(nt_bg)
ax[0].draw_artist(C_line)
ax[0].draw_artist(F_line)
ax[1].draw_artist(nt_line)
fig.canvas.blit(ax[0].bbox)
fig.canvas.blit(ax[1].bbox)
# pseudo-EM iterations to optimize the model parameters
if np.any(learn_theta):
if verbosity >= 1:
sigma, beta, lamb, gamma = theta_best
print(
'Params: iter=%3i; sigma=%6.4f, beta=%6.4f, '
'lambda=%6.4f, gamma=%6.4f; LL=%12.2f; delta_LL= N/A' %
(0, sigma, beta, lamb, gamma, LL_best))
n = n_best
C = C_best
LL = LL_best
theta = theta_best
nloop_params = 1
done = False
while not done:
# update the parameter estimates
theta1 = _update_theta(n, C, F, theta, dt, learn_theta)
# get the new n, C, and LL
n1, C1, LL1 = estimate_MAP_spikes(F, C, theta1, dt, spikes_tol,
spikes_maxiter, verbosity)
# test for convergence
delta_LL = -((LL1 - LL) / LL)
if verbosity >= 1:
sigma, beta, lamb, gamma = theta1
print(
'Params: iter=%3i; sigma=%6.4f, beta=%6.4f, '
'lambda=%6.4f, gamma=%6.4f; LL=%12.2f; delta_LL= %8.4g' %
(nloop_params, sigma, beta, lamb, gamma, LL1, delta_LL))
if plot:
C_line.set_data(fr_t, C1[:xmax] + theta1[1])
nt_line.set_data(fr_t[1:xmax], n1[:xmax - 1])
fig.canvas.restore_region(C_bg)
fig.canvas.restore_region(nt_bg)
ax[0].draw_artist(F_line)
ax[0].draw_artist(C_line)
ax[1].draw_artist(nt_line)
fig.canvas.blit(ax[0].bbox)
fig.canvas.blit(ax[1].bbox)
time.sleep(0.1)
# if the LL improved, keep these parameters
if LL1 > LL_best:
n_best, C_best, LL_best, theta_best = (n1, C1, LL1, theta1)
if (np.abs(delta_LL) < params_tol):
if verbosity >= 1:
print("Parameters converged after %i iterations" %
(nloop_params))
print "Last delta log-likelihood:\t%8.4g" % delta_LL
print "Best posterior log-likelihood:\t%11.4f" % (LL_best)
done = True
elif delta_LL < 0:
if verbosity >= 1:
print 'Terminating because solution is diverging'
done = True
elif nloop_params > params_maxiter:
if verbosity >= 1:
print 'Solution failed to converge before maxiter'
done = True
n, C, LL, theta = n1, C1, LL1, theta1
nloop_params += 1
if verbosity >= 1:
time_taken = time.time() - tstart
print "Completed: %s" % s2h(time_taken)
sigma, beta, lamb, gamma = theta_best
# correct for the offset and scaling we originally applied to F
C_best *= scale
beta *= scale
beta += offset
sigma *= scale
# since we can't use FNND to estimate the spike probabilities in the 0th
# timebin, for convenience we just concatenate (lamb * dt) to the start of
# n so that it has the same shape as F and C
n_best = np.concatenate((lamb * dt, n_best), axis=0)
theta_best = np.hstack((sigma, beta, lamb, gamma))
return n_best, C_best, LL_best, theta_best
def run_simulation(adjacency_matrix=None,
weight=None,
noise_rate=NOISE_RATE,
noise_weight=NOISE_WEIGHT,
resolution=RESOLUTION,
simtime=SIMTIME_RUN,
save=False, output_path='data/', basename='nest_sim_',
overwrite=False, verbose=True, print_time=False):
if adjacency_matrix is None:
# construct a network according to defaults
adjacency_matrix = fake_network.construct_network()
if weight is None:
# if unspecified, find the weight automatically according to defaults
weight, _ = adjust_weight(adjacency_matrix, noise_weight=noise_weight,
noise_rate=noise_rate, resolution=resolution,
verbose=verbose, print_time=print_time)
# convert into network_object
network_obj = adjacency2netobj(adjacency_matrix)
ncells, ncons, neuronsE, espikes, noise, GIDoffset = create_network(
network_obj, weight, noise_weight, noise_rate, resolution=resolution,
verbose=verbose, print_time=print_time,
)
if verbose:
print 'Simulating %s of activity for %i neurons' % (
s2h(simtime / 1000.), ncells)
startsimulate = time.time()
nest.Simulate(simtime)
endsimulate = time.time()
sim_elapsed = endsimulate - startsimulate
totalspikes = nest.GetStatus(espikes, "n_events")[0]
events = nest.GetStatus(espikes, "events")[0]
# NEST increments the GID whenever a new node is created. we therefore
# subtract the GID offset, so that the output cell indices are correct
# regardless of when the corresponding nodes were created in NEST
cell_indices = events["senders"] - GIDoffset
spike_times = events["times"]
burst_rate = determine_burst_rate(spike_times, simtime, ncells)
if verbose:
print "\n" + "-" * 60
print "Number of neurons: ", ncells
print "Number of spikes recorded: ", totalspikes
print "Avg. spike rate of neurons: %.2f Hz" % (
totalspikes / (ncells * simtime / 1000.))
print "Network burst rate: %.2f Hz" % burst_rate
print "Simulation time: %s" % s2h(sim_elapsed)
print "-" * 60
# resample at 50Hz to make an [ncells, ntimesteps] array of bin counts
resampled = resample_spikes(spike_times, cell_indices,
output_resolution=20, simtime=simtime,
ncells=ncells)
if save:
today = str(datetime.date.today())
fname = basename + today
if os.path.exists(fname) & ~overwrite:
suffix = 0
while os.path.exists(fname):
suffix += 1
fname = '%s%s_%i.npz' % (basename, today, suffix)
fullpath = os.path.join(output_path, fname)
np.savez(fullpath, spike_times=spike_times, cell_indices=cell_indices,
resampled=resampled)
if verbose:
print "Saved output in '%s'" % fullpath
return spike_times, cell_indices, resampled
